1. Field of Invention
This invention relates to electronic document reading systems. More particularly, this invention relates to electronic document reading systems that supplement a document with links to related portions of previously read and annotated documents.
2. Description of Related Art
When a person reads documents for comprehension, the reader establishes relationships between the document currently being read and other, previously read, documents. These relationships are then used by the reader to decide whether the new document should be read in detail (for example, because it complements previously read information) or if it should be skipped because it only duplicates the previously read documents.
Conventional systems and methods of conveying document interrelationships to the reader typically rely on graphical visualizations of documents where each document is represented by a point. One such system is described in xe2x80x9cBead: Explorations in Information Visualizationxe2x80x9d, M. Chalmers et al., Proceedings of SIGIR ""92, pp. 330-337, ACM Press (1992), incorporated herein by reference in its entirety. Document relationships can also be represented as a geometric shape. One such system is described in xe2x80x9cVisualizing Cyberspace: Information Visualization in the Harmony Internet Browserxe2x80x9d, K. Andrews, Proceedings of the IEEE Information Visualization Symposium ""95, pp. 97-104, IEEE Press (1995), incorporated herein by reference in its entirety. While these techniques efficiently represent very large numbers of documents, they do not effectively represent the content of those documents. By suppressing the document""s content when displaying relationships, these systems make it difficult for a reader to understand why and how the documents are related.
Remembrance Agent displays a list of documents that are related to the user""s current context while the user enters text. This system is described in xe2x80x9cA Continuously Running Automated Information Retrieval Systemxe2x80x9d, B. Rhodes et al., Proceedings of the First International Conference on the Practical Application of Intelligent Agents and Multi Agent Technology (PAAM ""96), pp. 487-495 (1996), incorporated herein by reference in its entirety. However, Remembrance Agent does not encourage reading or browsing, because the suggestions are ephemeral and thus disappear when additional text is entered. Furthermore, Remembrance Agent does not consider the user""s interests. No preference is given to passages that the user found interesting or relevant over other, potentially irrelevant, portions of documents.
Bookmark Organizer presents a hierarchical list of documents, but leaves it to the user to find the appropriate documents. This system is described in xe2x80x9cAutomatically Organizing Bookmarks Per Contentsxe2x80x9d, Y. Maarek et al., Computer Networks and ISDN Systems, 28 pp. 1321-1333 (1996), incorporated herein by reference in its entirety. In addition, although bookmarks identify the potentially interesting documents, they do not identify the passages that are of specific interest.
There is thus a need for an electronic document reader that supplements new documents with selectable links to relevant and annotated portions of previously read documents.
This invention provides a system and method that automatically constructs relationships among segments of different documents. Portions of a document that have been identified as being interesting to a user are extracted from previously read documents. These portions may have been explicitly identified to the system by the reader or the relevance of the portion may be inferred by the system based upon cues, such as annotations, made to the documents by the user. The identified portions, or xe2x80x9csurrogatesxe2x80x9d, are indexed and linked to the original documents and are used as proxies for the user""s various interests. The portions are clustered based upon their relatedness to each other. Therefore, each cluster of portions relates to a topic.
When a new document is opened it is segmented into passages and the passages are compared to the portions from the previously read documents. If a passage of the new document is identified as being closely related to a portion then a selectable link is provided in the new document to the old document from which the identified portion originated. The user may then choose to select the selectable link to the old document to read the portion of the old document to enhance understanding of the new document by reminding or refreshing the understanding of the reader. In this manner a user""s understanding of a new document is enhanced.
These and other features and advantages of this invention are described in or are apparent from the following detailed description of the preferred embodiments.